A. Field of Invention
This invention pertains generally to cathode ray tube (CRT) alignment and more particularly to the use of processor and memory within a host computer to store, process, and transfer necessary correction factor data to align video displays on CRT devices.
B. Definitions
Align means to cause a video image to be adjusted so that distortion characteristics are reduced and the video image that is displayed on a display forms an image that is pleasing to the eye.
Bi-directional connector means any electrical, optical, electromagnetic or other type of connection that is capable of transmitting information in at least two directions, either on a separate cable or other link, the same cable or link, during horizontal or vertical retrace, or during trace if over a separate cable or link.
Cathode ray tube monitor means a cathode ray tube and one or more of the following: associated circuitry, windings, coils, electron guns and other similar devices.
Characterization module means a device that includes storage such as non-volatile memory for storing correction factor data or an identification number for the display. The characterization module can also store term multipliers or parametric data for use in aligning a display that employs standard transformation equations.
Connector means any electrical, optical, electromagnetic or other type of device or system for making a connection.
Correction and driver circuitry means one or more of the following: digital to analog converters, interpolation engine, pulse width modulators and pulse density modulators, as well as summing amplifiers, oscillators, op-amps, inverters comparators and/or any other components necessary to generate correction signals.
Correction control data means correction factor data that has been processed for a particular set of monitor settings and/or a particular location of a video image on a display screen.
Correction factor data comprises encoded digital bytes or any other form of data or signal that is representative of the distortion characteristics of a display for one or more correction factor parameters. Correction factor data may include data from a vision system, a gain matrix table, and/or manually generated data relating to geometry or distribution characteristics, as well as other correction factor parameters of the display. Correction factor data may take the form of term multipliers or parametric data that is used to adjust standardized transformation equations.
Correction factor parameters include various geometry characteristics of a display including horizontal size, raster rotation, vertical size, horizontal center, vertical center, pincushioning, vertical linearity, keystoning, convergence, etc, and various electron gun characteristics including contrast, brightness, luminosity, focus, color balance, color temperature, electron gun cutoff, etc.
Correction signals means any of the signals generated by the correction and driver circuitry, and/or the control and driver circuits, correction factor data and correction control data.
Decoder means a device for generating, transforming or modifying a signal or other data in response to one or more input signals including data inputs. For example, a decoder may be a pulse width modulator, a pulse density modulator, a digital to analog converter, an interpolation engine, a lookup table, a processor, etc.
Display means a device or system for viewing a video image that includes cathode ray tube monitors.
Disposed in means physically placed in association with another device.
Distortion characteristics means the amount of any particular type of distortion as indicated by the distortion data measured at a number of different points on a display.
Distortion data means a signal or other data that is representative of the distortion characteristics that exist on a display with regard to the geometry characteristics of the display, and/or electron gun characteristics of the display. For example, distortion data can be measured as a result of misalignment of a video image or improper amplitude or gain of a video signal.
Electronic storage medium means an electronically operated device or component that is capable of storing information.
Filters means any type of signal conditioner including integrators.
Host computer means any apparatus having a processor that is used in conjunction with a display, including computers, television receivers, set top boxes, etc.
Host processor means a device capable of processing data that is not disposed in a display.
Integrators means a type of signal conditioner that performs a time integration of an input signal.
Located externally to means placed physically outside of another device.
Magnetic storage medium means a device that is capable of storing information using a magnetic medium.
Memory comprises any desired storage medium including, but not limited to, EEPROMS, RAM, EPROMs, ROMs, magnetic storage, magnetic floppies, bar codes, serial EEPROMs, flash memory, optical storage magneto-optical storage, DVD, etc., or any improvements of these types of storage or other types of storage.
Monitor RAM means any type of storage or memory.
Optical storage medium means a device that is capable of storing information using an optical medium.
Processor means a logic device including, but not limited to, state machines, micro-processors, digital signal processors, etc.
Serial connector means a connector that is capable of transmitting data serially.
Set top box means a host computer used in conjunction with a television receiver.
Storage means any type of storage device or memory for storing data including magnetic storage media such as floppy disks, optical storage media, non-volatile memory, magneto-optical storage, devices, compact disks, etc.
Summing amplifiers means devices that are capable of combining a plurality of input signals such as disclosed in U.S. patent application Ser. No. 08/611,098 filed Mar. 5, 1996 by James R. Webb et al. entitled "Method and apparatus for Making Corrections in a Video Monitor".
Television receiver means a device that receives either a digital or analog television signal and transforms the television signal into a video signal for display on a cathode ray tube monitor.
Video image means a displayed image that appears on a display screen that is produced in response to a video signal.
Video signal means an electronic signal that is representative of video image data.
C. Description of the Background
Recent developments in the automated measurement of display device distortion parameters such as cathode ray tubes and the automated alignment of CRT displays, in devices such as computer monitors and digital television sets, have made it possible to correct video displays for numerous types of distortion. Presently, these corrections are performed within the CRT device by an advanced digital monitor board using a dedicated processor and memory. As the ability to correct for various types of video distortions has increased, the memory size and processor speed required to automate video image alignment has become more expensive and has increased the cost of CRT devices using these systems. These costs have effectively limited the use of automatic alignment techniques to only the most expensive CRT devices. This has prevented use of dynamic alignment techniques in the majority of CRT monitors manufactured today. Therefore, it would be desirable to implement automatic distortion correction without a dedicated processor in the monitor and to minimize the memory required within the monitor or CRT device. Such new implementations would allow automated distortion correction to be extended to the large number of low cost CRT devices not presently using these techniques. It is against this background and these problems and limitations that the present invention has been developed.